You can user CHAR or NUMBER datatype for your requirement. Create filed with datatype CHAR(1), or a NUMBER(1) and allow values such as Y/N, or 0/1 respectively. You can use constraint also on the field so that you can have only the allowed values.

Have you ever had to make fundamental changes to a table in Oracle, but haven't been able to get any downtime? I'm talking things like:
* Dropping columns
* Shrinking allocated space
* Removing chained blocks and restoring the PCTFREE
* Re-or…

Using SQL Scripts we can save all the SQL queries as files that we use very frequently on our database later point of time. This is one of the feature present under SQL Workshop in Oracle Application Express.